Okay. We all know about the partisan divide in this country - Democrats, Republicans - but there's another political divide. Part of the country is very engaged in the political process and part is not.

RENEE MONTAGNE, HOST:

Older Americans, richer Americans and better educated Americans are more likely to be politically engaged. Now researchers have found one more factor that seems to shape political engagement, the length of your commute. It comes to our attention as MORNING EDITION focuses on commuting.